I'll bet this has been asked before

[cubpilot]

Part 91 is not the issue. Part 91 operations can depart in any weather which allows them to land somewhere.

Once on the final approach Part 121 & 135 are like part 91 in that “flight visibility” determines if you can continue to a landing.

The issue is before takeoff (and before beginning the final approach) reported weather is the controlling factor. Is it visibility alone or does the ceiling apply too.

That said, maybe it is only visibility. I can’t find personally anything that proves otherwise. Someone else did post an interpretation that indicated both must be considered. I’d like to hear from some 121/ 135 drivers about how their companies apply this rule. It was a long time ago so I can’t remember how, but I believe I lost a similar argument in which I claimed the other side, back when I flew under part 135. Our company used both for the “reported weather” requirements.

 

[Deltoid]

Try and look at the difference between 135 & 121.


Here is the excerpt from 121.===>

(b) Except as provided in paragraph (d) of this section, no pilot may continue an approach past the final approach fix, or where a final approach fix is not used, begin the final approach segment of an instrument approach procedure -
(1) At any airport, unless the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, issues a weather report for that airport; and
(2) At airports within the United States and its territories or at U.S. military airports, unless the latest weather report for that airport issued by the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, reports the visibility to be equal to or more than the visibility minimums prescribed for that procedure. For the purpose of this section, the term "U.S. military airports" means airports in foreign countries where flight operations are under the control of U.S. military authority.

Notice 121 is verify specific as to the requirement of visiblity only...
Now look at 135====>


§ 135.225 IFR: Takeoff, approach and landing minimums.
{New-2003-21 (a) revised September 17, 2003, effective November 17, 2003}
(a) Except to the extent permitted by paragraph (b) of this section, no pilot may begin an instrument approach procedure to an airport unless--
(1) That airport has a weather reporting facility operated by the U.S. National Weather Service, a source approved by U.S. National Weather Service, or a source approved by the Administrator; and
(2) The latest weather report issued by that weather reporting facility indicates that weather conditions are at or above the authorized IFR landing minimums for that airport.

It says nothing about visiblity. But what it does say is minmums. Minimums is plural, meaning more than one, ceiling and visibility. When the FAA means visibility they will say it just as they do for 121. Furthermore there are interpretations on this issue for 135 and they are very clear as to the FAA's intent. So in a nut shell both are required for 135. I have been a check airmen and chief pilot for a 135 jet and turboprop company and have dealt with this issue enough times and have had my guys abide by the interpretation. Now that I have been flying 121 for years I could see how needing both would kill the 121 industry for getting to destinations.

Here is the interpretation from washington enforcement.

March 21, 1991
Mr. Glenn Rizner
Technical Specialist, Membership Services Department
Aircraft Owners and Pilots Association
Frederick, MD 21701-4798

Dear Mr. Rizner:

We recently received a letter from the Assistant Chief Counsel for the Eastern Region of the Federal Aviation Administration asking us to give a legal interpretation of a question you posed to them concerning Part 135 of the Federal Aviation Regulations (FAR). We apologize for the delay in answering your query.

The question was: Are both ceiling and visibility required in order for an FAR Part 135 air carrier pilot to initiate an instrument approach?

FAR 135.225(a) and 135.225(a)(2) forbid a Part 135 pilot from beginning an instrument approach unless reported weather conditions at the destination airport are at or above the authorized IFR landing minimums for that airport. So, even though ceiling is not a criterion on the approach plates, it must be considered by the pilot in his decision to initiate the approach, and in deciding whether the reported ceiling is above or below the decision height or minimum descent altitude for the approach. Similarly, FAR 135.225(b) forbids initiation of a final approach segment unless reported conditions are at or above minimums. Again, the pilot must know the reported ceiling and visibility before deciding whether that approach segment can legally be initiated.

This interpretation has been coordinated with the Air Transportation Division of the Flight Standards Service. We hope that this satisfactorily answers your question.

Sincerely,

/s/

Donald P. Byrne
Assistant Chief Counsel
Regulations and Enforcement Division




I hope this clears it up..


Deltoid

 

[HAL]

Deltoid,

Thanks for the info. I do understand the interpertation as you posted in your last message. However my original question deals with the decision whether or not to launch, not start the approach. It is FAR 135.219 that I was concerned with, regarding whether or not you can go if the ceiling is low but visibility is good. I do have a problem with the FAA saying, in essence, "Ceiling is not required, but we'll violate you if we feel like it. Sort of a catch-22.

Either you can go, or you can't. Allowing the PIC to make a decision, then have the FAA say you can't seems a little arbitrary.

HAL

 

[cubpilot]

Hal

This is an interesting topic so I keep poking my nose in where it probably shouldn’t be but here goes anyway.

From 1985 – 89 I flew metros for a commuter airline and both visibility and ceiling were required. I am now thinking we were operating with a letter of interpretation from our POI principal operations inspector, which means it was not likely given to anyone other than our carrier. The language was very similar to the letter cited by Deltoid, only our letter applied to any time reported weather was required. ie before take of, and before beginning the approach. The letter came about as a result of a similar discussion to this line. Someone asked, maybe me, if only visibility was controlling how did we apply the 100’ increase in ceiling requirement for a new captain?

Now I am asking anyone. How does the 100’ increased ceiling for new captains apply in 121?

As for your original question about current and forecast. The length of time a current observation is valid depends on some circumstances about the observation. Hourly station reports are made hourly with special reports made if the weather has a significant change. A significant change is defined to include, an increase or decrease in ceiling or visibility above the landing minimums of published instrument approaches for the field. Also I have seen letters, which explain that a weather report becomes invalid, when the observer leaves the field. While it is true that the observation is like a snapshot, these other considerations lead me to believe that hourly reports have a validity of up to one hour.

Next FAR 135.219 states in part “…the latest weather … indicates that the weather will be…” The word indicates was interpreted by our POI as giving the PIC the responsibility to use his judgment to decide what the combination of reports indicated. The specific example given for this was the forecast was for below minimums expected improve later (too later) to above minimums. Yet a trend of hourly reports showed that the improvement was actually ahead of forecast, the flight could depart.

You seem to be vary capable to exercise good judgment with regards to weather. So I assume you are more concerned here with the legal technicalities of this. My suggestion is to ask the POI which oversees your company. Be specific and ask as many questions as needed to cover all the scenarios. Then ask for a letter from him. If you get one, it will serve as a good faith effort to comply with the rule. Effectively making the rule what ever the letter says until you get a letter from someone with higher authority telling you, your other letter is wrong. Another technique, which is useful when you get verbal directives, but the POI is reluctant to put it in writing, is a reverse confirmation letter. This is where you write back some thing like “Thank you for answering my questions on the phone yesterday. From our conversation I understand …”
If the interpretation is reasonable, this should protect you from a legal catch-22, pending a better interpretation.

 

[Deltoid]

Hi Hal,

I was reading so many posts I lost track of original question. Here is an excerpt from washington in regards to using reports or forecasts to launch.

You ask if the above operations can be conducted under PAR Parts 121 and 135 when the weather forecast calls for conditions at or above minimums but the hourly sequence reports indicate that weather conditions are below minimum (examples 1 and 3). You ask also about the situation where the forecast is for conditions below minimums but the hourly sequence reports indicate that weather conditions are at or above minimums (examples 2 and 4).
FAR Section 121.613 states, in pertinent part, that an aircraft cannot be dispatched or released for operations under IFR or over-the-top unless appropriate weather reports or forecasts, or any combination thereof, indicate that the weather conditions will be at or above the authorized minimums, AT THE ESTIMATED TIME OF ARRIVAL at the airport(s) to which the aircraft is dispatched or released. Section 135.219 requires that in order to take off and operate an aircraft under IFR or over-the-top, the latest weather reports or forecasts, or any combination of them, must indicate that weather conditions AT THE ESTIMATED TIME OF ARRIVAL at the next airport of intended landing will be at or above authorized IFR landing minimums. With regard to alternate airports, Section 121.625 states, in pertinent part, that no person may list an airport as an alternate airport unless the appropriate weather reports or forecasts, or any combination thereof, indicate that the weather conditions will be at or above the alternate weather minimums specified in the certificate holder's operations specifications for that airport WHEN THE FLIGHT ARRIVES. Similarly, Section 135.221 requires that in order for an airport to be designated as an alternate airport, the weather reports or forecasts, or any combination of them, must indicate that the weather conditions will be at or above authorized alternate airport landing minimums for that airport AT THE ESTIMATED TIME OF ARRIVAL.

{p24}

The above cited regulations clearly indicate that the critical time period for purposes of determining whether an aircraft can be dispatched or operated under IFR conditions or whether an airport can be listed as an alternate is the estimated time of arrival. Weather forecasts which indicate that conditions will be at or above minimums at ETA are sufficient for operations under FAR Parts 121 and 135, even if hourly sequence reports state that weather conditions are currently below minimums. It follows that weather forecasts which indicate that conditions at ETA will be below minimums are not sufficient for such operations, despite what hourly sequence reports may indicate."


Essentially you can operate IFR based on forecast alone. The reg years ago was changed from report AND forecasts to reports or forecats so use may use the favorable of the two. Now remember you are 135 so you need ceiling and visiblity to even start the approach so if the forecast ceiling is below and visibility is good you still can't go if it is forecast as such. Its logical because if you cant' start the approach you should not even be going anyway.

Avbugs post is correct but only after the final approach segment has been started but does not address before hand the planning or starting a trip.



As for cub pilots question for a high mins captain..

§ 121.652 Landing weather minimums: IFR: All certificate holders.
(a) If the pilot in command of an airplane has not served 100 hours as pilot in command in operations under this part in the type of airplane he is operating, the MDA or DH and visibilitylanding minimums in the certificate holder's operations specification for regular, provisional, or refueling airports are increased by 100 feet and one-half mile (or the RVR equivalent). The MDA or DH and visibility minimums need not be increased above those applicable to the airport when used as an alternate airport, but in no event may the landing minimums be less than 300 and 1.

Again the FAA is very specific. MDA or DH and Vis is increased. This is the only time where a 121 pilot is limited by ceiling when flying and for good reason until they gain experience. Now it also says in NO EVENT can it be less than 300 & 1. No event means nada, zip, never in legal terms. After the math what ever is derived with the additives you are limited to a minimum of 300 & 1. Eg. an 1800rvr approach plus 2400rvr additive equals 4200 so you bump it to 5000rvr which is 1 mile. So if the report prior to final approach segment has a 200' & 3 miles the high min captain is screwed because in "no event" may it be less than bla bla. At our carrier this is how we operate in regards to high mins.
Now if you have started the final approach the NO EVENT would catch you if it is reported below while on the approach. No event leaves no option. They way I read it is if you derive a ceiling of lets say 450' & 1 mile and you start the final approach and a report comes in at a ceiling of 300' & 1 mile you are still good to continue since the visibility is controlling now and its above 1 mile. Any thing less than that you get into the "NO EVENT" regime.
In any event consult your OPS SPECS and if you can, like someone mentioned in a prior post, get a letter if you can from your POI. Some will be reluctant because of liability so don't be surprised if they will not do it.


Have a good one

Deltoid

 

[HAL]

cubpilot,

You are right of course - I believe I have enough decision making ability to decide what is the right course of action, and am only looking for the exact legal interpetation. And I do think asking my POI is a good idea.

At the risk of overload, here the essence of my question is this: The FAR says (as deltoid pointed out) it is the weather at the estimated time of arrival that is important in making the decision (by 135.219) whether or not to take off. Now, if you have a five minute flight, the METAR says it is fine to go but the TAF forecasts below minumums, of course you can go. If it is a two hour flight, you can't go. My question is, where is the break between the 'current conditions' and forecast becoming predominant in making your decision.

I fully understand the 121 regs, as I've spent most of my career in 121 ops. Because of a furlough I'm now flying 135 and trying to make sure I don't confuse the issue between the two types of flying.

HAL

 

[avbug]

A METAR doesn't describe current conditions. It describes past conditions. Much like an annual inspection says about the current airworthiness of an airplane...the METAR speaks to the past. While the ink is wet on the signature of the IA performing the annual inspection, the aircraft can be unairworthy...the inspection buys the past, not the future. The same for the METAR. It speaks to the time of the observation, and no further.

The TAF, even if it covers the same time period, speaks to the future, and takes priority.

As for ceiling being controlling, it is never controlling. Even in the case of the high minimums captain; the captain isn't controlled by ceiling. Only visibility. However, one will have a harder time making the case that the flight visibility is above minimums when the ceiling is below the minimum descent altitude for the approach.

When a high minimums captain must add to the minimum descent altitude of decision altitude for the proceedure in use, no "ceiling" has been established for that captain. Only proceedural minimae.

The actual ceiling is no more limiting for a high minimums captain than it is for any other routine operation, weather Part 121 or Part 135.

What your POI has to say on the subject is opinion, but has no legal basis...and the POI has no authority to issue a "letter of interpretation." Visibility is controlling. One may be held to have violated the regulation where the ceiling is reported below minimums, as official data exists which shows that the lowest reported layer being broken or overcast, is below the minimum descent altitude for the proceedure...the burden of proof then comes on you to show that you had adequate visibility at the time...unless you take a photograph, you may be out of luck.

Remember that it's up to you to prove innocense; the FAA doesn't need to prove it's case, as the circumstantial facts of a report below minimums are more than enough. You are guilty until proven innocent, and you may require more than an "I had the required visual references in sight" to counter an official weather report or observation, to the contrary.

 

[Deltoid]

Hi Hal,

This is the most you will get out of the FAA on the subject of departure decision making.

The rationale behind the current regulation is that as long as one can show a combination of weather reports or forecasts indicating above minimum weather conditions at the estimated time of arrival (ETA) at the destination airport, the flight may be dispatched or released. However, the converse is also true, that when any combination of weather reports or forecasts show below minimum weather conditions at the destination airport at ETA, the aircraft may not be dispatched or released.

The key thing is ETA and no part of the forecast including prob40 or temp can have anything below mins. Metars may be past info but it is a report never the less. When its provided by an A02 system you can call the number to get a live report. Thats what I would do. Also get past Metars to paint a weather trend picture and see if its contrary to or in line with the forecast. You can even get a weather depiction chart off these WSI stations to see whats happening around the airfield. Its a report as well. It may be a little stale but you can see the surface front positions and surround conditions.

Avbug writes:

"As for ceiling being controlling, it is never controlling. Even in the case of the high minimums captain; the captain isn't controlled by ceiling. Only visibility. However, one will have a harder time making the case that the flight visibility is above minimums when the ceiling is below the minimum descent altitude for the approach. BINGO !!!!!!

When a high minimums captain must add to the minimum descent altitude of decision altitude for the proceedure in use, no "ceiling" has been established for that captain. Only proceedural minimae. " Correct.....

Your right about visiblity controlling but my point is that the FAA violated our guys because the high min captain shot an approach to a 100 & 1 reported cat I because he was on low fuel and had not declared an emergency to deviate from 121.652. They got him on going below his 300' limit. Their reasoning is excactly what you mentioned about how will you have a mile vis with a ceiling below your limit. They contended he should not have started the approach and deverted or delcared a fuel emergency giving him carte blanc... Thats why our high mins guys will not start the approach when the ceiling is below the high mins limit. Otherwise its reported visiblity for non high mins guys to begin the approach.

This is great discussion. Keeps me up on this..

Good day Guys.

Deltoid

 

[AAsRedHeadedbro]

Just to add a quick two cents to this discussion, under current FAR part 121 dispatch rules along with a certain exemption given to my carrier (I believe it's 3585 but I can not be absolutely certain since I don't have my ops specs with me at home), we are allowed to depart for the destination airport when the CONDITIONAL language of the forecast indicates that the visibility may be below that required for an approach to that airport (The MAIN body of the forecast must indicate visibility at or above the minimum visibility value for the planned approach). The exemption requires that the visibility value in the conditional section be no less than 1/2 the required visibility for the planned approach and requires a SECOND alternate to be filed. The exemption goes on to say that the forecast for the FIRST alternate airport must indicate in the conditional remarks section values of no less than 1/2 the required visibility AND ceiling required for the planned approach to be used. Additionally, the SECOND alternate must indicate that visibility AND ceiling will be at or above minimums for the approach planned for that airport in both the main body AND the conditional remarks section. No reductions of any kind are allowed for the second alternate with respect to dispatch requirements.

So it appears that the FAA has allowed exemptions to be used at some (if not all) part 121 air carriers with regards to dispatch to destination airports that are forecast to possibly be below minimums, based on conditional language. The FAA apparently has modified its stance somewhat since the letters posted by Avbug were first published in the late 1980's.